Thesis: Transcriptome analysis of insecticide resistant Drosophila suzukii

Drosophila suzukii, also known as spotted wing Drosophila (SWD), is an invasive agricultural pest that is a threat to berry production due to a serrated ovipositor on female flies that enables them to lay eggs in soft-skinned, ripening fruits. Currently, growers rely heavily on the use of insecticides to manage D. suzukii. Over the past six years, insecticide resistance has been detected in D. suzukii in California, but the molecular mechanism underlying this adaptation is unknown. Therefore, we sought to identify the molecular mechanism conferring insecticide resistance in these pests. We generated isogenic lines from field-collected resistant populations and sequenced the transcriptomes of two pyrethroid- and two spinosad-resistant lines. In both pyrethroid-resistant isogenic lines and one spinosad-resistant line, we identified an overexpression of metabolic genes that have been previously implicated in insecticide resistance in other insect pests. In the other spinosad-resistant line..., , , # Transcriptome analysis of Drosophila suzukii reveals molecular mechanisms conferring pyrethroid and spinosad resistance

CA Tabuloc, CR Carlson, F Ganjisaffar, H Zhang, CC Truong, C Chen, KM Lewald, S Hidalgo, FG Zalom, JC Chiu
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# Data generated from Illumina short-read sequencing (PE150) and PacBio long-read sequencing (Two 8M SMRT cells). RNA was extracted from isogenic lines developed from unsprayed Drosophila suzukii collected from populations resistant to either pyrethroid insecticide (specifically zeta-cypermethrin) or spinosad insecticide on either strawberries (S) or caneberries (C).

Female D. suzukii flies were entrained at 25C in 12-hour light:12-hour dark cycles for two full days. On the third day, flies were collected on dry ice sixteen hours after lights-on (ZT16). This time point was selected because D. suzukii was previously observed to exhibit a low level of cytochrome P450 expression at this time (Hamby et al., 2013). This means any overexpression may be more eas...